LINN^EAN SOCIEXT OF LONDOX. 



31 



geographical zoiiss the complete disappearance of the feature may 

 be finally reached. 



The Oriental species of the Danaine genus Tirumcda possess * 

 a very distinct V-shaped mark at the inner end of area 2 of the 

 hind wing, in the acute angle between vein 2 and the cell. Most 

 of them have also a smaller mark of the same form at the inner 

 end of area 3, One .'African species of the genus, T. petiverana, 

 barely distinguishable from the common Oriental T. Uraniace or 

 T. septentrionis, possesses the V-mark fully developed. Three 

 other species, one of them separable into two subspecies, evidently 

 represent a much earlier invasion, and are greatly modified — so 

 much so indeed that Moore placed them in a separate genus, 

 Melinda. I thought it would be of interest to study the fate of 

 the Y-mark in these four forms, of wiiich two are East African 

 and therefore near the original home, one Central, and one 

 Western. In addition to specimens in the Oxford University 

 Collections, I have been enabled, by the kindness of Lord 

 l-iothschild, to examine material from Tring. The result of the 

 enquii-y is shown in tabular form below. 



^ The trace on L. side only of one d. R- O'lly o' another and of one 2 . 



^ The mark of the value of III on II. side, of IV ou L. of one of the three 

 males. 



^ The trace apparently represented by a single pale scale on L. side only of 

 one of tiio two males. 



^ A very minute III. The pale tint much dimmed and not bright as in the 

 other forms 1-3. 



* T. neptiinia of Fiji has lost tliis mark on the upper surface, retaining a 

 trace below. The change is part of a general darkening in mimicry of local 

 Enploeas. 



